Jazmin has always been overweight, unlike her skinny, cousin Mia. Jazmin wins a trip to Palm Springs for the weekend at a five-star resort. She and best friend Stacey find the first day at the spa embarrassing, as hotel robes don't fit, and the massage table is quite small for their thick figures. They leave in frustration to join Mia, who has been ogling a Nigerian man swimming in the pool. He introduces himself as Tunde, but Jazmin is shocked, too distracted to remember her own name. He and his friends find Jazmin and Stacey beautiful. However, they think Mia is so skinny that they wonder if she is sick. They invite the women out, with Tunde saying he has never seen such beautiful women in America.

Tunde and Jazmin begin dating but before they consummate their relationship she grows jealous and makes a scene when she sees him having dinner with a white woman instead of having dinner with a colleague like he told her. Tunde reveals the woman was his colleague but Jazmin, realizing she will forever be jealous and think Tunde will leave her, breaks up with him and leaves Palm Springs. At home she is depressed and comforts herself with food before having a breakthrough and realizing she is beautiful and worthy of being loved. Bursting with new confidence, Jazmin approaches the head buyer of the Bloomfields where she works and shows him her designs. Impressed he helps develop Jazmin's fashion line "Thick Madame" becomes popular and is launched worldwide.

One year later, she to travels to Nigeria to apologize to the man she realizes she loves. A woman opens the door holding a baby. Jazmin asks if she is Tunde's wife, and the woman agrees. Jazmin has the girls go to the taxi because she does not like to be rejected with an audience. She tells Tunde that he has changed her life, but she won't be a "homewrecker". Tunde clarifies that the woman is a maid, he delivered the baby, and the maid doesn't understand English. He says his prayers have been answered, as he has loved Jazmin all along. They share a passionate kiss, and he promises to handle only her. Mia and Stacy also reunite with their partners, and they join Tunde's family for dinner. Mia piles food on her plate, stating that she wants to bulk up so she can find a rich Nigerian doctor as well. The film ends with Jazmin and Tunde in bed, while Jazmin insists on having the lights on to see every sexy thing on Tundes body With the credits ending.

In its opening weekend, the film grossed a total of $3,109,924 in the United States. As of July 9, the film has grossed a total of $7,061,128 in the United States. The film is considered to be successful because it made its $3 million production budget back in its first weekend of release. It only made $340,762 overseas and thus has only made $7,401,890 worldwide.[1]

The film received mostly negative reviews, with Rotten Tomatoes reporting that out of 43 reviews, 10 were "Fresh" and 33 "Rotten", making for an overall 23% approval rating and the consensus: "Although Phat Girlz has good intentions, it is sloppily made and thin on laughs." The film has a slightly higher score of 36/100 on Metacritic, indicating "generally unfavorable" reviews. The San Francisco Chronicle praised the film, saying "Clumsily directed yet entertainingly written by Oakland native Nnegest Likké, Phat Girlz is like Rocky with cellulite. Or maybe Pretty Woman without all the bony butts. It has a lot of heart and soul, but it's almost never mean-spirited."[2]

Variety magazine's Joe Leydon said that the film "feels torturously padded at an overlong 98 minutes",[3] and also claims that the romance between Jazmin (Mo'Nique) and Tunde (Jean-Louis) is too drawn out, "quite possibly because writer-director Nnegest Likke has nothing else in her scenario to sustain audience interest".[3]Entertainment Weekly gave the film a D grade, remarking that "Mo'Nique is fat. Almost every scene in Phat Girlz — the fancy z is for Z-grade — is about how she's fat",[4] and concluding that "the movie reduces her to a single discernible characteristic, which is a telltale mark of many a wholly awful comedy."[4]